With development of display technology, liquid crystal displays (LCDs) become more and more popular due to its advantages such as portability, low radiation and the like. A major issue puzzling the LCD is the issue of image sticking which generally includes area sticking and line ship sticking, where the line ship sticking is generated for the reason that the direct component caused by pixel voltage difference between the two adjacent frames on a certain row in certain pictures acts on liquid crystal molecules for a long time. For example, a certain picture is a black-write interleaving picture, where the 99-th and 100-th rows are white and the 101-th row is black, and when the broadcast television transmits interleaved scanning signals, that is, only odd rows or even rows of signals are transmitted; for example, at the time of the N-th frame, signal which is white on the 99-th row and black on the 101-th row is transmitted; that is, only the odd rows are transmitted, and the data on the 100-th row is automatically calculated at a display terminal and a grey picture is generated between the black and the white; at the time of the (N+1)-th frame, the broadcast television transmits signals on even rows; in this case, a real signal on the 100-th row will be transmitted, which is a white picture; it can be seen that, pixel voltages on the 100-th row are different between the N-th row and the (N+1)-th row; therefore, the direct component is generated, and the line ship sticking will be generated for the reason that the direct components act on the liquid crystal molecules for a long time.
A present approach to solve the issue of the image sticking is POL (Polarity Inversion) inversion, and the POL is a signal for controlling polarity of pixels; for example, as shown in FIG. 1, a row of pixels are scanned every half of a period, and each row of pixels possess two preset polarity arrangements; when the POL is at the high level, one of the two polarity arrangements is selected, and when the POL is at the low level, the other of the two polarity arrangements is selected; for example, for an individual pixel, the polarities thereof are +-+-+- in a plurality of frames; if the POL inversion is performed at the fourth frame, after the POL inversion, the polarities of this pixel are +-++-+ sequentially in the same several frames; that is, the original polarity of the pixel is inverted once; with alternative POL inversion, the direct component can be correspondingly inverted, so that the direct components are cancelled with each other in a time period and elimination of the line ship sticking is achieved. However, the pixels are charged twice with a same polarity in a frame in which the POL is inverted, overshooting is formed, so that in a static picture, human's eyes can perceive that the brightness of this frame is increased, that is, a flicker occurs.